Request node js and twitch api

API
2

You declared application/json but (likely) sent application/x-www-form-urlencoded

So try

const options = {
    method: "POST",
    url: '',
    body: JSON.stringify({ ...snip ... })
    },
    headers: {
      'Authorization': '... ',
      'Client-Id': '...',
      'Content-Type': 'application/json'
    }
  };